Dairy Industry Research

Research had been a major activity in the Department of Dairy Industry ever since science has taken precedence over practice. Earlier work of the department -- the interest of C. L. Roadhouse in milk flavors -- set the tone of research. Milk flavors and their attendant spin-offs -- chemistry of flavor constituents, mechanisms of enzyme action, identification of specific enzyme systems, and sensory evaluation -- have formed a principal area of research and one in which the Department has become noted.

Following World War II, the enactment of the California Industry Advisory Board Act -- later designated as California Dairy Council -- for the first time provided substantial and dependable (for a while) funds for expansion of research. At the end of the war, dairy production had been stimulated by the need to provide substantial amounts of dairy foods for the armed forces and the civilian economy -- a most beneficial effect of nutritional knowledge. With the prospects of large surpluses the dairy industry was confronted by the need to absorb these surpluses or face economic disaster. The CDIBA Act was California's answer and its main provisions supported advertising, education and research based on moneys collected from both produces and processors. With some lobbying by University officials, a sum of $50,000 per year was required to be allocated to the University for research in dairy products. This came at a time when the department was under-staffed and the industry had little idea of the areas in which the money should be spent. Consequently, an improvised program was set up based largely on immediate practical problems of the industry -- ice cream shrinkage, skim milk surpluses and similar trouble shooting approaches. However, the department was able to incorporate some programs of fundamental and lasting value, such as chemistry of milk fat, physiology of lactic acid bacteria, influence of heat on lactose-milk proteins interactions and a few others. All of these projects have produced information of substantial value to the industry and to the public at large. Unfortunately, with one to two exceptions, all the fundamental projects have been since rejected by the Council and only those that promise immediate returns have been retained. Incidentally, the legal requirement for allocations of specific amount was dispenses with after two to three years and the allocations since that time have been at the discretion of the Council (or Board).

Despite loss of assurance of research funds, this activity provided a nucleus for the establishment of a sound research program within the department and, while it operated to reduce the size of normal appropriations from within the university, it has served a useful purpose. More recently, grants from the National Institutes of Health of the U.S. Dept. of Health, Education and Welfare have been obtained to provide needed research funds. Again, unfortunately, projects to be acceptable to NIH must be couched in such terms as to relate to problems in which the allocating committee has a special interest.

Most of the research of the department had its origin, appropriately, in the need to provide scientific data that could be applied to specific problems of the industry. Palatable milk is a requisite for adequate milk consumption and Dr. Roadhouse early turned is attention to two of the most troublesome off-flavors of that time -- feed flavors and oxidized flavor. He was assisted for many years in these studies by J. L. Henderson and the work has been continued by W. L. Dunkley. Some of the more significant results of these researches have been the nearly universal adoption of changed feeding practices to prevent the absorption of feed flavors; the great reduction in the incidence of oxidized flavor through the elimination of oxidative catalytic metal, principally copper, that come into contact with milk; the effects and variations of naturally-occurring copper on oxidized flavor; and the influence of light rays of different wave lengths on the development of off-flavors. While the problem of off-flavors still persists, it has been greatly reduced and a vast body of information useful in its control has been, and is still being, obtained.

Another flavor problem, hydrolytic rancidity, was first noticed in butte, but later recognized in all dairy foods. Dr. Tarassuk has devoted most of his scientific career to the study of this problem. As a result, the enzyme systems responsible have been identified and their mode of action determined. Thus, general principles governing the activity of these enzymes have been established and applied to control the defect in various dairy products. Furthermore, Tarassuk and his associates have been successful in separating one of the lipases to a high degree of purity and characterizing its chemical composition.

Understanding the physiology of lactic acid bacteria is fundamental to the proper control of fermentations in dairy products manufacture. Some work in this area was started by Mudge and F. L. Smith while in the department, but it remained for E. B. Collins to develop the work to where practical applications could be made. His studies made it possible to set up a program for controlling bacteriophage in lactic acid fermentations which has been adopted nationwide with marked success.

The occurrence of "sandiness" in ice cream led Nickerson to a study of lactose crystallization and later to the relationship between crystal size and shape and protein stability at low temperature. This work is being continued as related to frozen concentrated milk and similar products which are subject to protein destabilization and settling.

Jennings had gained recognition in two principal fields of research: the chemistry of volatile flavors and the mode of action of cleaning solutions. Through concentration of volatiles occurring in minute quantities he has been able to identify and characterize their chemical nature and give additional insight into the complex nature of milk. Through the application of physical laws to the study of solution action in removing soil from surfaces, he has developed general principles, expresses as mathematical equations, that govern this phenomenon. This has made possible a logical approach to cleaning equipment by cleaning equipment by cleaning-solution circulation.

For a number of years there was wide discussion about the relative nutritional merits of milk fat and fats of plant origin. To develop knowledge on which reasonable judgments could be made, Henderson and the author undertook a study of the chemistry of milk fat to learn its detailed composition and structure. The chemical studies were supplemented for several years by nutritional studies . The nutritional studies indicated that perhaps one fraction of milk fat supported greater growth than the others but the results were inconclusive and this phase of the study was discontinued. L. M. Smith has continues this research, making major contributions to the knowledge of milk fat composition and structure and particularly of milk phospholipids. These studies have reveal the detailed composition of milk lipids, the detailed structure of unsaturated fatty acids and location within the glyceride molecule of the individual fatty acids.

Many other short term researches have been completed in the department. Among these are: a study by Richardson and Abbott on temperature treatment of cream to prevent "sticky" butter; control of foaming in casein manufacture by Tarassuk; milk and solids-not-fat in California milk on which the State Department of Agriculture based a milk pricing formula; detailed composition of California milk by Nickerson; control of cottage cheese spoilage by Collins; and Dunkley's application of rancidity control to pipeline milking systems. In addition, there have been studies of various sorts on dry milks, numerous researches on cheese manufacture, development of analytical techniques applicable to research problems, resistance of various stainless steel alloys to corrosion, ice cream texture studies and a host of others. The author apologizes if he has omitted specific mention of any studies the investigators think should have been included. The omission, if any, are the consequence of a poor memory and not of intent.